1. Field
Devices consistent with exemplary embodiments relate to active optical devices employing refractive index variable regions.
2. Description of the Related Art
Optical devices such as a lens, a mirror, and a prism are variously used as a means for changing a path of light in optical systems. In general, an optical device is formed of a material having a fixed refractive index value, and is processed in its form to change a path of light. Accordingly, a very complicated structure is required to control, as desired, a path of light in an optical system.
As a method capable of solving the complicity, active optical devices capable of controlling a refractive index according to an external signal attract attention. A representative active optical device is a polymer-dispersed liquid crystal (PDLC) device. In the PDLC device, a refractive index of liquid crystals varies according to whether an electric field is applied, and thus a difference in refractive index occurs between the liquid crystals and a polymer adjacent to the liquid crystals to cause a difference in optical path. However, a PDLC device has a high driving voltage, which causes a scattering phenomenon due to liquid crystal droplets, and thus has a problem in practical use.